Plasma Volume Calculator
HealthEstimate plasma volume from height, weight, sex, and hematocrit using Nadler's formula. A standard reference calculation, not a clinical planning tool.
Estimated Plasma Volume
2.46
Estimated Total Blood Volume
4.25
What is a Plasma Volume?
The Plasma Volume Calculator estimates plasma volume — the liquid, non-cellular portion of blood — from height, weight, sex, and hematocrit. It builds on Nadler's formula for total blood volume, then adjusts for the red blood cell fraction.
For the underlying blood volume calculation, see the Blood Volume Calculator.
How to use this Plasma Volume calculator
- Enter your height in centimetres.
- Enter your weight in kilograms.
- Select your sex.
- Enter your hematocrit percentage.
- Read the Estimated Plasma Volume and Estimated Total Blood Volume instantly.
Formula & Methodology
Total Blood Volume is calculated using Nadler's formula (see the Blood Volume Calculator for details). Plasma Volume = Total Blood Volume × (1 − Hematocrit %) Worked example — a total blood volume of 5.25 L with a hematocrit of 42%: Plasma Volume = 5.25 × (1 − 0.42) = 5.25 × 0.58 = 3.05 L
Frequently Asked Questions
Plasma volume is the liquid, non-cellular portion of blood, calculated as total blood volume minus the fraction occupied by red blood cells (hematocrit).
The calculator first estimates total blood volume using Nadler's formula from height, weight, and sex, then multiplies that by (1 minus hematocrit as a decimal) to isolate the plasma portion.
Hematocrit represents the percentage of blood volume occupied by red blood cells, so subtracting that fraction from total blood volume leaves the remaining plasma (liquid) volume.
No — this is an educational reference calculator only. Actual fluid management and plasma volume assessment must be determined by a qualified healthcare professional based on the complete clinical picture.
This calculator builds directly on the [Blood Volume Calculator](/blood-volume-calculator/)'s Nadler formula estimate, adding a hematocrit adjustment to isolate the plasma-specific portion.
Hematocrit typically ranges around 38-50% in healthy adults, varying by sex and individual factors, though your specific value should come from an actual blood test rather than an assumption.
Plasma volume is relevant in various physiological and research contexts, including understanding fluid distribution and certain medication dosing calculations that reference plasma volume specifically rather than whole blood volume.
This calculator expresses plasma volume in litres (L), the same unit used for the underlying total blood volume estimate.
Yes — plasma volume can shift relatively quickly due to factors like hydration status, posture, and other physiological changes, which is part of why hematocrit itself can fluctuate somewhat between measurements.
Nadler's formula is one widely referenced method; other formulas and direct measurement techniques also exist, though Nadler's remains one of the most commonly cited reference equations.
Also known as